1. Field of the Invention
This invention relates to a new electrical system for controlling the operation of a heat exchanger means and to a new thermostat for such a system as well as to a new method of making such a system and a new method of making such a thermostat.
2. Prior Art Statement
It is well known to provide an electrical system for controlling the operation of a heat exchanger means, the system having a first electrical power source, the system having an electronic control logic unit operatively interconnected to the first power source to operate the heat exchanger means in relation to data means selectively entered into the electronic control logic unit and being maintained by the electronic control logic unit as long as the electronic control logic unit is receiving electrical power, the system having a second electrical power source for supplying electrical power to the electronic control logic unit to maintain the data means thereof when the first electrical power source ceases to supply electrical power to the electronic control logic unit even for a relatively long period of time, the second electrical power source comprising a battery, such as a rechargeable battery.
For example, see Perkins, et al, U.S. Pat. No. 3,948,441 for an example of a thermostat having a rechargeable battery as a back-up second electrical power source and while this patent does not disclose an electronic control logic unit, see the Hart, U.S. Pat. No. 5,102,042 for a disclosure of such an electronic control logic unit for a thermostat.
It is also well known that capacitors have been utilized for short-term electrical power back-up, such as to maintain operation for a few minutes while batteries are changed or to cover brief power outages of a few seconds or less. However, applicant is not aware of any use of capacitors as a possible replacement for a battery in an electronic thermostat.